The present invention relates to applicators and more particularly but not exclusively to an applicator to deliver a viscous liquid.
The present invention relates to the manual pumping of liquids and more particularly but not exclusively to thick or viscous liquids such as cream, mayonnaise, mustard, sauce etc.
In fast food outlets it is not unusual to have teenagers (particularly young girls) working in food preparation areas. Frequently their tasks will include the application of the above mentioned viscous liquids.
Previously known applicators have suffered from the disadvantage that they are typically designed for adults having considerable hand strength. These previously known devices are therefore most unsuitable to be used in instances where the liquid to be pumped is viscous.
Many manual operated applicators, such as those used in delivering a medication to animals, include a cooperating piston and cylinder, with the piston being spring-urged to a position maximizing the volume within the cylinder. Operation of the applicator compresses the spring which in turn provides a resistance from the view point of the operator. This resistance can be considerable.
It is the object of the present invention to overcome or substantially ameliorate the above disadvantages.
There is disclosed herein an applicator to deliver a liquid, said applicator comprising:
an interacting piston and cylinder enclosing a first chamber from which the liquid is delivered by the applicator and a second chamber to receive liquid to be delivered to the first chamber;
a liquid outlet extending from said first chamber;
a liquid inlet extending to said second chamber;
a one-way valve connecting said first chamber with said second chamber for the transfer of liquid from said second chamber to said first chamber; and
means to cause relative reciprocating movement between the piston and as cylinder to vary the volume of said second chamber and said first chamber to deliver liquid from said first chamber when the volume thereof is decreased while delivering liquid to said second chamber as the volume thereof increases, and delivering to said first chamber from said second chamber liquid as the volume of said second chamber decreases and the volume of said first chamber increases.